1. Field of the Invention
The present invention relates to a noise filter with an improved noise filtering effect whose basic structure is a feedthrough capacitor and which is imparted an effect of a distributed constant filter, and more particularly, to that suitable for use in a circuit of data processing equipment and communication equipment.
2. Description of the Related Art
Electronic equipment such as data processing equipment and communication equipment in recent years is mostly digitalized, and further, the frequency of digital signals handled in these equipments is becoming higher in accordance with the increased speed of data processing capability. Accordingly, noises generated from these equipments similarly tend to increase in a high-frequency range. As a noise countermeasure, many of these equipments use electronic components for preventing electromagnetic interference and inhibiting unnecessary voltage fluctuation. Multilayer feedthrough capacitors are in general use as such electronic components for noise countermeasure.
Here, a multilayer feedthrough capacitor 110 being a multilayered type feedthrough capacitor for noise countermeasure, which is shown in FIG. 21 to FIG. 23, will be described below.
As shown in FIG. 22(A), FIG. 22(B), and FIG. 22(C) the multilayer feedthrough capacitor 110 has one dielectric sheet 122 on which a first internal conductor 112 led out to two side faces opposite to each other and serving as a signal conductor is disposed, and two dielectric sheets 124 on each of which a second internal conductor 114 led out to two side faces different from the abovementioned two side faces and serving as a grounding conductor is disposed. These dielectric sheet 122 and dielectric sheets 124 are stacked to form a multilayer body 120 shown in FIG. 21.
Further, a pair of terminal electrodes 132A, 132B both connected to the first internal conductors 112 are disposed on both ends of the multilayer body 120, and a pair of terminal electrodes 134A, 134B both connected to the second internal conductors 114 are disposed on both side faces of the multilayer body 120. Accordingly, the pair of terminal electrodes 132A, 132B are connectable to a signal line side and the pair of terminal electrodes 134A, 134B are connectable to a ground side. In the multilayer feedthrough capacitor 110, the first internal conductors 112 and the second internal conductors 114 constitute a capacitor C as in an equivalent circuit diagram shown in FIG. 23.
However, the frequency handled in recent electronic equipment has become remarkably higher, which further increases noises, and the lowered power consumption of the electronic equipment lowers operating voltage. Consequently, noise resistance of the electronic equipment is deteriorating. Under such circumstances, multilayer feedthrough capacitors have been used in many electronic equipments and have exhibited an effect as noise filters which are electronic components for noise countermeasure, but there has arisen a demand for a higher noise filtering effect.